Tank Mounting problems of the 2008 Cadillac CTS

Driving up a hill in PA. We were on state highway 118 near sweet valley PA. Car bucked and jerked violently. Car stopped running in middle of roadway with traffic backed up behind me. Eventually cars worked their way by me and I was able to drift car back to a place where I could get it off the road and out of the way. Very harrowing experience. Very unsafe. Car was towed in as it would not restart. Tow truck driver also tried to restart to move car to optimum place to put car on flatbed. Car would not restart. After diagnosis the dealership said that: car only had 3 gallons of gas in tank and this was not enough to get up hill. Gas gauge showed between 1/8 to 1/4 of tank. No low fuel light. The dealership said that it might not happen again, but that it could. After returning to my home in FL I took it to the selling dealer. They called Cadillac and Cadillac agreed with both dealerships that there was nothing wrong but that due to the design of the gas tank, the car could stall going up a hill at any time unless a significant amount of gas was in the tank. They would not define significant. They said that gas had sloshed to the rear of the gas tank and the gas pickup was sucking air. They say that after car was towed 30 miles on a flatbed gas sloshed to the front of tank and engine could be started. They said that nothing could be done. This is a very, very unsafe condition. The guy behind us almost hit us as we decelerated rapidly. And then a whole line of cars almost collided. Cadillac says that nothing can be done. I say that something must be done to protect drivers of all 2008 Cadillac Cts.